Here is a working example similar to your question - Demo192.limesurvey.org/index.php?sid=65354&lang=en

It asks you to enter the ages of your children in descending order. The multiple numeric question has 4 sub-questions named sq1-sq4, so the Question validation equation is:

q1_sq1 >= q1_sq2 && q1_sq2 >= q1_sq3 && q1_sq3 >= q1_sq4

and the question validation tip is

You must enter the ages of your children in descending order

There is a new CSS style called em_q_fn_validation that controls the visibility of this message. The default templates prevent this from appearing until the page has been submitted. However, you can change that default so that that message appears immediately whenever the user enters a value that is not in descending order.